To Study The Genotoxicity Effect And Mechanismof Graphene Oxide

Objective:To study the genotoxicity effect of graphene oxide（GO）and investigate its mutagenic effect and related mechanisms which provide a basis for the safe application of GO in the biological field.Methods:Part one:1.The representation of GO.The morphology of GO was observed by transmission electron microscope（TEM）.The chemical composition of GO was analyzed by Fourier transform infrared spectroscopy（FTIR）.The chemical state and surface composition of the main elements of GO were analyzed by X-ray photoelectron spectroscopy（XPS）.The structure of GO was analyzed by X-ray diffraction（XRD）.2.The effects of GO on acute toxicity in mice:70 mice were randomly divided into seven groups,and3.28、4.096、5.12、6.4、8、10 mg·kg^-1doses of GO suspension were injected via tail vein to observe the toxic reaction and death of mice,and the lethal amount of 50%(LD₅₀)was calculated.Part two:according to the technical guidelines for drug genetic toxicity research,Ames test,in vitro CHL cell chromosome aberration test and mouse chromosome aberration test were used to study the genetic toxicity of GO at the level of bacteria,cells and overall animals.Part three:Mechanism of genetic toxicity induced by GO.1.Genetic toxicity induced by GO and degree of oxidative stress injury in lung tissue.study on the effects of GO on lung and liver toxicity and its mechanism.According to the weight of 60 male mice were randomly divided into 6groups,each group of 10 mice,with 2000μg·kg^-1、1000μg·kg^-1、500μg·kg^-1、250μg·kg^-1、125μg·kg^-1dose tail intravenous injection once a week,normal control group injected amount of normal saline,10 mice in each group at 7,14,28 days after weigh executed and profile control in lung,viscera index calculation,using the corresponding kit test lung tissue SOD activity and MDA content and GSH-Px levels.2.The proliferation inhibition rate of A549 cells treated with GO at 50μg·m L^-1、100μg·m L^-1、200μg·m L^-1、400μg·m L^-1、600μg·m L^-1、800μg·m L^-1、1000μg·m L^-1concentrations was determined by MTT assay.The LDH release in the supernatant of A549 cells was detected with the lactic dehydrogenase（LDH）assay kit.Apoptosis detection kit was used to detect the influence of apoptosis and necrosis of A549 cells;Cell cycle detection kit was used to detect the blocking effect of GO on A549 cell cycle.Results:1.GO,with a size of about 100nm,is a transparent,cotton-like sheet structure with abundant oxygen-containing functional groups.In this study,the LD₅₀of mice was 6.577 mg·kg^-1,and the 95%confidence interval was（5.879～7.452）mg·kg^-1。2.GO had no mutagenic effect in the Ames test in vitro,but in the chromosomal aberration test at the cell level and in vivo level,GO had potential genetic toxicity,showing different types of structural chromosomal aberrations,and the chromosome aberration rate increased significantly with the increase of GO concentration.This indicated that GO induced genotoxicity was positively correlated with dose.3.GO with a concentration greater than 400μg·m L^-1can significantly inhibit the proliferation rate of A549 cells,induce the formation and release of LDH and cause cell membrane damage,leading to apoptosis and necrosis,and a high rate of cells entering the late stage of apoptosis and necrosis.At the same time,it can also induce cell cycle arrest at G₀/G₁stage and inhibit cell mitosis.4.GO with a dose greater than 500μg·kg^-1can significantly reduce the SOD activity,GSH-Px content in lung tissues,and significantly increase the content of organ index and MDA.Conclusion:GO has potential genetic toxicity,and its mechanism may be related to the increase of apoptosis and necrosis,the increase of cell cycle arrest in G₀/G₁phase,and the increase of oxidative stress injury.